How does PHP handle session cleanup when using the $_SESSION array?

When using the $_SESSION array in PHP, it is important to properly clean up session data to prevent the accumulation of unnecessary data in the server's memory. This can be achieved by periodically clearing out expired sessions using session garbage collection. PHP provides a built-in function session_gc() that can be used to perform this cleanup process.

// Perform session garbage collection to clean up expired sessions
session_gc();